Systems of that kind are known, for example, in the form of implantable cardiac pacemakers, defibrillators or corresponding items of equipment for eliminating arrhythmia states of the heart or for the electrostimulation treatment of other parts of the human body.
The corresponding items of equipment generate electrical' pulses or other signals that act on the human body or provide therapeutic effects in response to signals sensed from the body. Control from the exterior is however also a possibility.
The previous devices of that kind suffer from the disadvantage that they could generally only process information in a direct relationship with the therapy; that is, information which in terms of time and also as regards processing of the signals, were very close to the direct therapy and which therefore were comparatively easy to manage in terms of the cause-effect linkage. In regard to the example of a cardiac pacemaker, this means that, to control the stimulation effect, those signals which are directly correlated with the outcome of the treatment were picked up from the heart. The simplest example in this respect is represented by a demand pacemaker which artificially produces heartbeats by stimulation whenever natural heartbeats fail. It will be apparent that here it was sufficient to have a simple timer which is resettable by a natural heartbeat in order to implement that device in regard to its basic function.
In a situation involving more complex arrhythmia states, however, the linkage relationships of signals to be picked up by sensors in the body are much more complicated.